Field of the Invention
The present invention pertains to a novel process for the preparation of Fluoroalkylpyrazole- or Bisperfluoroalkypyrazole carboxylates comprising a cyclization of Perfluoroalkyl ketoesters with hydrazines.
Description of Related Art
N-Allyl-3-Perfluoroalkyl-5-Fluoropyrazoles carboxylates are important intermediates for the preparation of agrochemical active ingredients, particularly of fungicides. Correspondingly, N-Alkyl-3-Perfluoroallcyl-5-Fluoropyrazoles carboxylates are described, for example, in the synthesis of fungicidally effective pyrazole carboxamides derivatives (cf e.g. WO 2010/130767), or in the synthesis of fungicidally effective arylalkylpyrazolecarboxamide derivatives and analogues (cf e.g. WO 2011/151370).
Usually, 3-Perfluoralkyl-5-Fluoro pyrazoles carboxylates are prepared via multistep transformations starting from acetoacetates. The preparative process of 5-fluoro-1-alkyl-3-fluoroalkyl-1H-pyrazole-4-carbonyl chlorides from 5-chloro-1-alkyl-3-fluoroallcyl-1H-pyrazol-4-carbaldehyde is disclosed in WO 2011/061205.
Proceeding from this prior art, the object of the present invention is to provide an improved one step process for the preparation of Fluoroalkylpyrazole- or Bisperfluoroalkypyrazole carboxylates derivatives which can be carried out easily and cost-effectively. The Fluoroalkylpyrazole- or Bisperfluoroalkypyrazole carboxylates obtainable using this desired process should preferably be obtained with high yield and high purity. In particular, the desired process should allow the desired target compounds to be obtained without the need for complex purification methods.
This object is achieved by a novel process for the preparation of Fluoroalkylpyrazole- or Bisperfluoroalkypyrazole carboxylates.